On Thu, May 27, 2021 at 05:03:09PM +0200, Miquel Raynal wrote: > Hi Colin, > > Colin King <colin.king@xxxxxxxxxxxxx> wrote on Thu, 27 May 2021 > 15:50:48 +0100: > > > From: Colin Ian King <colin.king@xxxxxxxxxxxxx> > > > > Currently there are corner cases where spec_times is NULL and > > chip->parameters.onfi or when best_mode is zero where ret is > > ^ > something is missing here, the sentence is not clear > > > not assigned a value and an uninitialized return value can be > > returned. Fix this by ensuring ret is initialized to -EINVAL. > > I don't see how this situation can happen. > > In both cases, no matter the value of best_mode, the for loop will > always execute at least one time (mode 0) so ret will be populated. > > Maybe the robot does not know that best_mode cannot be negative and > should be defined unsigned, but the current patch is invalid. > People think list counter unsigned is a good idea, but it's a terrible idea and has caused hundreds of bugs for me to fix/report over the years. *grumble*. Anyway, I was revisiting this code because it showed up as a Smatch warning and the bug appears to be real. best_mode = fls(chip->parameters.onfi->sdr_timing_modes) - 1; The "onfi->sdr_timing_modes" comes from the hardware in nand_onfi_detect() and nothing checks that it is non-zero so "best_mode = fls(0) - 1;" is negative and "ret" is uninitialized. regards, dan carpenter
